Over recent years, systems that perform monitoring over a wide range using videos captured by a plurality of video cameras (imaging apparatuses) have been devised. PTL 1, for example, discloses a monitoring system that tracks a moving body captured by each of a plurality of cameras. In the method described in PTL 1, using feature values such as brightness values, colors or the like of moving bodies extracted from respective cameras, identicalness of the moving bodies is determined.